The field of the invention relates generally to circuit breakers and more particularly to monitoring circuit breaker operation over time.
Circuit breakers are often used to protect, in a residential, industrial, utility, or commercial environment, against overcurrent conditions, ground fault conditions, or other system anomalies that are undesirable and require the circuit breaker to open. In some circuit breakers, an electronic control system, referred to as a trip unit or an electronic trip unit or a relay, monitors one or more characteristics of electrical power to detect the presence of overcurrent conditions and causes an operating mechanism to separate circuit breaker contacts upon detection of an overcurrent condition by the trip unit. Separating the circuit breaker contacts, generally referred to as “tripping” the circuit breaker when caused by protection reasons or opening the circuit breaker when caused by control reasons, interrupts the flow of current through the circuit breaker.
In industrial settings, for example, the electronic control system serves to prevent damage to equipment and machines that, in many cases, represent a significant investment by a business and on whose operation the business relies. The electronic control system carries out this function by monitoring electrical current through a line. If the current exceeds a certain threshold, the electronic control system opens a circuit breaker on the line, thereby preventing excessive current from reaching devices or conductors that would be damaged by the excessive current. Circuit breakers may also be utilized in a variety of other applications.
Over a period of time, circuit breakers may degrade, resulting in slower switching times for both opening and closing operations. As a switching time increases, the quality of the protection provided by the circuit breaker to prevent excess current from reaching downstream devices may be degraded. Degraded circuit breakers can be maintained, repaired, or replaced to maintain acceptable performance levels. However, in at least some known power distribution systems, maintenance personnel may not be aware that a circuit breaker is degrading until the circuit breaker becomes wholly inoperable or the circuit breaker is called upon to operate and then operates slower than desired or initially planned.